Corrosion inhibiting compsoitions



U nit-ed States Patent 3,169,116 CORROSION I rit- COMPOSITIONS MauriceS. Baseman, 5899 Hobart StgKeith C. Johnson, 3745 Brownsville Road; andSherwin E. Baseman, 2212 Shady Ave, all of Pittsburgh, Pa.

No Drawing. Filed Feb. 2, 1960, Ser. No. 6,108

9 Claims. ((Il. 252-77) r This invention relatesto petroleum basecompositions which may be applied asflcoatings to metal surfaces toprovide for. corrosion inhibition ofythe metal surfaces,

through the vapors produced by the compositions or by 7 contact of thecompositions with the metal surfaces.

The prevention of corrosion of metal surfaces and weight loss therefromhas been a: considerable problem particularly when such surfaces areexposed to the elements including rain, snow, and high humidity. Inaddition, acidic. atmospheric conditions have to a large extentaggravated the :corrosion problem. These problems of corrosion are ofprimary importance not only inthe ferrous metals field, but alsoofconsiderable importance for many of the non-ferrous metals. 1 J

It has been desirable to apply to metal surfaces some quickly and easilyapplied and readily removed coating which gives good corrosionprotection. .It has also been desirable that the coating be of such anature that the applied material is not undesirable or detrimental whenthe treated article is put to its intended use, or when corrosionprotection is no longer of prime concern.

Previously proposed special wrappings and packaging treatments withdehumidification are costly and diificult. Slushing compounds such asheavy oils and greases have been employed but the applied products areoften unsightly, are diflicult and expensive to remove, and are notcompletely satisfactory in preventing corrosion under many conditions.Furthermore, such slushing compounds ordinarily must be applied tobone-dry metal surfaces. Coating formulations embodying organic amidesand inorganic metal nitrites have been employed. Other formulationscontaining ammonium derivatives, ureas, and the like have also beenemployed. Coatings embodying either of these last aforementionedmaterials have not been sufiiciently satisfactory inasmuch as many ofthem produce rapid and disastrous weight loss on many non-ferrousmetals, especially on copper, brass, zinc, and cadmium, or

they are not of sufficient strength or volatility to efliciently inhibitcorrosion. formulations incorporating ammonium salts are not completelysoluble in hydrocarbon vehicles at practical working concentrations.Further, compositions, which cause excessive weight loss on copper andbrass especially, exclude a large portion of the metals industry field,inasmuch as many finished metallic products contain combinations offerrous metals and non-ferrous metals,

It is also desirable to have available a'corrosion inhibiting additivewhich is not only solublein hydrocarbon solvents such as benzene andtoluene, but has a-relatively It has been found also that many3,159,,ii5 Patented Feb. 9, 1965 caprylic acids. v

A further object of this invention is to provide a highly effectivecorrosion inhibiting composition comprising a major proportion of apetroleum base vehicle, a minor proportion of the reaction product of acycloaliphatic amine, a mixture of caproic and caprylic acids,methylbenzylamine and hydrophilic wetting agent.

Other objects will in part be obvious and will in part appearhereinafter.

This invention is. based upon the discovery that a certain combinationof amines reacted with suitable acids exhibits synergistic corrosioninhibiting characteristics whereby it is highly effective in the vaporphase, in the liquid contact phase, and, produces no deleterious effectson ferrous metals, copper, brass,'and alloys and combinations of copper,brass, and ferrous metals.

In particular, it has been discovered that the reaction product of acycloaliphatic amine, particularly dicyclohexylamine, methylbenzylamineand a mixture of caproic and caprylic acids will dissolve both inhydrocarbons and in water, and imparts exceptional corrosion inhibitingproperties to oleaginous liquids, paints and aqueous coating'compositions. From 15 to 0.1 parts of this reaction product, andpreferably at least- 2 parts, admixed with an oleaginous liquid to give100 parts by weight of a composition, provides an excellent protectivecoating material. The composition should comprise at least 75 partsby'weight of the oleaginous liquid and preferably from 8,0 to 98 partsthereof. From 10 to 0.1 parts, and preferably from 5 to 0.5 parts, of anoil soluble hydrophilic I wetting agent maybe present to enable thecomposition to be applied to damp or Wet metal surfaces.

7 We have discovered that the reaction productof substantially equimolarparts of caprylic acid and dicyclohexylamine is relatively insoluble inwater. The solubility caproate-caprylatc reaction product will dissolvein 90 good solubility in water. Many paints and coating com- Y actionproduct of a mixture of caproic and caprylic acids and a cycIic amine. r7

Another object of this invention is to provide a' corrosion inhibitingadditive of controlled alkalinity and moderate vapor pressure, andcapable of being dissolved in hydrocarbon solvents and in water,comprising the reaction prodw duct of at least 9 weight percent ofcaproic acid and the grams of Water. This effect is obtained whenalphamethyl benzylamine is substituted for up to half the weight of thedicyclohexylamine or when cyclohexylamine 'is substituted in whole or inpart'for the dicyclohexylamine. These compositions are all substantiallycompletely soluble in hydrocarbon solvents such as toluene, benzene, andthe like.

The following compositions of Examples I to IV illustrate the watersolubility features of the invention:

. EXAMPLE 1 A mixture'comprising 95 parts of dicyclohexylamine, 40

parts of alpha methylbenzylamine, 'lQ'parts of caproic acid and parts ofcaprylic acidwas stirred at room temperature and it reacted to form aproduct in afewminutes. When ten gramsof the reaction product wasadmixed With 90 grams of water at 25 C., 22% of the reaction productdissolved. When ten grams of a similar reaction product containing nocaproic acid was admixed .100 poises.

with 90 grams of water it did not appreciably dissolve in the water.

EXAMPLE II A mixture of 95 parts of dicyclohexylamine, 40 parts of alphamethylbenzylamine, '14 parts of caproic acid and 86 parts of caprylicacid was reacted as in Example I. When ten grams of this reactionproduct were placed in 90 grams of water at 25 C., 84.4% of the reactionproduct dissolved.

EXAMPLE III The proportions of the reactants in Example 11 were variedto provide 12 grams of caproic acid and 88 grams of caprylic and theremaining ingredients being unchanged. When 10 grams of the reactionproduct was placed in 90 grams of water at 25 C., it dissolved to theextent of 68.8% by weight.

EXAMPLE IV EXAMPLE V I A. From 75 to 99.8 parts, by weight, of anoleaginous vehicle, such as petroleum oil, of a viscosity. ofcentipoises to 100 poises at 20 C.;

B. From to 0.1 parts, by weight, of an oil soluble hydrophilic wettingagent such as petroleum sulfonates and sorbitan monolaurate; and

C. From 15 to 0.1 parts, by weight, of the reaction product of (a) from80 to 135 parts of dicyclohexylamine, (b) from 45 to 0.1 parts ofalpha-methyl-benzylamine, (c) from 91 to 75 parts of caprylic acid and(d )from 9 to 25 parts of caproic acid.

EXAMPLE VI A. From 85 to 99.9 parts, by Weight, of an oleaginous vehicleof a viscosity of 5 centipoises to 100 poises at C.; and

B. From 15 to 0.1 parts, by weight, of the reaction product of (a) from80 to 135 parts of dicyclohexylamine, (b) from 0.1 to 45 parts ofalpha-methyl-benzylamine, (c) from 91 to 75 parts of caprylic acid and(d) from 9 to parts of caproic acid.

Small amounts of the order of up to 10% of the weight of the compositionmay comprise other corrosion inhibiting additives such as phosphates(zinc phosphate), chromates (sodium chromate), and organic corrosioninhibitors (diisopropylamine nitrite), thickening agents such aspolyisobutylene, and anti-oxidants such as dimethyltertbutyl phenol.

The oleaginous vehicle is preferably a relatively nonvolatile materialof a viscosity from 5 centipoises to 50 poises at 20 C. However, certainapplications may require a vehicle of a viscosity from 1 centipoisethrough Suitable oleaginous vehicles are petroleum hydrocarbon oils, andparticularly oils of a viscosity of 5 poises to 25 poises at 100 F.,vegetable oils such as castor oil, and synthetic oils such as long chainesters of dibasic acids for example bis(2-ethyl-hexyl) seb'aca'tes andthe like sold in the trade as Ucon fluids.

Numerous oil soluble hydrophilic wetting agents may be employed inpreparing the compositions. Petroleum sulfonates or mahogany soaps ofwhich sodium and barium mahogany sulfonates are examples, are quitesatisfactory. Sorbitan monolaurate, sorbitan monopalmitate, sorbitanmonooleate and sorbitan polyoxyethylene derivatives, such as thosesorbitan monopalmitate polyoxyethylenes sold as Tween 40 and Tween 80,are other examples of suitable wetting agents.

The reaction product may comprise (1) 100 parts by weight of a mixtureof the monocarboxylic fatty acids composed of at least 9 parts ofcaproic acid and at least parts of caprylic acid; (2) from to 135 partsby weight of dicyclohexylamine or cyclohexylamine, or mixtures of thetwo; and (3) from 0.1 to 45 parts by weight of alpha-methylbenzylamine,the total of (2) and (3) being from 80.1 to 150 parts. Particularly goodresults arehad using 25 to 15 parts of caproic acid and from 75 to partsof caprylic acid. 1

The alpha methylbenzylamine performs an important function in theadditive component for vapor phase protection applications. A series offive separate reaction products was prepared in which constantproportions comprising 15 parts of caproic acid and 85 parts of caprylicacid were employed, while a total of 125 parts of dicyclohexylamine andalpha methylbenzylamine were employed, the latter varying from alldicyclohexylamine to all alpha-methylbenzylamine. A small quantity ofseveral grams each of the five reaction products was placed in glasscylinders 8 inches tall'and 2 /2 inches in diameter with a tapered neckwhich was closed with a cap. After a sample was put in a glass cylinder,an alkaline indicator strip was placed at the neck and capped. The timefor the vapors to reach the neck and charge the indicator was noted aswell as the pH of the vapor. A low alkalinepH of about 8 is. mostdesirable since higher alkalinity will result in corrosion of metals.Also slow volatilization of the alkaline vapors is desired for longeffective life of the composition in service. However, an extremely slowvapor evolution is not adequate to provide good corrosion protection.The following table indicates the results of these tests:

Table I Ratio of Dicyclohexyl- Time pH amine/Methylbenzylamine 125/0 3'48 /15 2'52 8 95/30 137" 8 80/45 16" 8 W Mo 10 Composition 5 isessentially useless because of its excessive vaporization rate andexcessive alkalinity. Compositions 3 and 4 bore excellent pH values anddesirable rates of vapor evolution. Compositions 1 and 2 evolve alkalinevapors rather slowly and would not be acceptable for many applications.

Alpha methylbenzylamine also improves the elfect of the compositions oncopper and copper base alloys. At least three parts ofalpha-methylbenzylamine per one hundred parts of dicyclohexylamine willprevent a copper reaction from occurring.

The reaction product may be prepared and then dissolved in a smallamount ofxylol or kerosene or other organic solvent and then added tothe oleaginous vehicle. For ease of production the reaction product maybe made by adding the caprylic and caproic acids, dicyclohexylamineandalpha-methylbenzylamine directly to the oleaginous vehicle. Stirring oragitation of the mixture then completes the reaction and disperses thereaction product throughout the vehicle. The oleaginous vehicle, thehydrophi lic wetting agent, the dicyclohexylamine, thealpha-methylbenzylamine, the caprylic acidand the caproic acid may beadmixed together in any order.

Jet engine fuels that are stable and non-corrosive when stored in steeldrums may be prepared from kerosene and a quantity of the reactionproduct of from 0.5% to 0.1% in weight admixed therein.

The composition comprising the additives in oils may be applied to metalmembers by dipping, brushing, spraycovering film of the composition willbe present to protect the metal surface. The metal to be treated may bedamp or wet with water, and quite cold, but the composition willdisplace the moisture readily from its surface. V

' The composition may bejp'laced in close proximity to the metal member,the metal member is then packaged or enclosed so that the packagesituation or enclosure contains the metal member and a quantity of the"compounded oleaginous material. The vapors produced by the compositionwill afford highly effective corrosion protection to the metal membetrs.i

The reaction product compositions of the present invention are highlysuited for incorporation in amounts of up to 15% into fluid compositionscomprising substantial proportions of water and aqueous media (from 10%to 90%) as one componentand oleaginous fluids both synthetic andnatural. Thus, for example, hydraulic fluids comprising aqueousemulsions of petroleum oils or synthetic polyesters and hydrolubes whichmay comprise water, ethylene glycol and a high viscosity liquid such asphosphate ester, chlorinated biphenyl and polyglycol, each may betreated toincorporate from 0.1% to or more, by Weight of the corrosioninhibiting reaction product compositions of the present invention. Thereact-ion product compositions will readily dissolve in the aqueous.phase of the emulsions or the hydrolub es and confer corrosionresistance in the liquid phase as well as the vapor phase. When suchtreated emulsions and other aqueous phase hydraulic lubricants areemployed as brake fluids and in hydraulic drive mechanisms they willimpart excellent corrosion resist-' ance to all portions of theapparatus exposed to the compositions and their vapors.

Niunerous metal Working lubricating compositions T comprise a mixture oremulsion of (a) Water or a Water solution, often containing slurry of asolid lubricant or non-abrasive filler such as lithopone, and (b) ahydrocarbonaceous material such as oils and bitumens, as Well as anemulsifier such as a cationic amine salt and an extreme pressure agent,for instance, a haloorganophospha'te such as monobutyltrichloromethanephosphorate.

. The addition of the reaction products of the present invention to suchaqueous metal lubricants in amounts of up to 15% Will reduce rusting andcorrosion of the metal while it is being machined, drawn or otherwisebeing Worked and prevents corrosion while the metal is stored or furtherprocessed.

Sheet metal members, casting, wire strip, fabricated member's, shipinteriors, barrels, bearings, crankcases, r

are examples of products that may be treated. Barrels, crankcase-s, gearboxes, transmission cases or other enclosed objects as well as packagedor closed structures will be elfectively protected by the oleaginousvehicle composition containing from 0.1 to 3% of the dicyclohexylaminealpha methylbenzylamine caprylate caproate product. Totally exposedmembers or members subjected to wet or highly humid conditions should becoated with compositions having from 3% to 15% of thedicyclohexylamine-alpha-m-ethylbenzylamine octoatecaprylate and at least3% of a suitable wetting agent.

Examples of metals which may be effectively protected comprise steel,cast iron, 12% chromium iron or other lower moderately stain resistantsteels, copper, brass, and aluminum.

In all cases of application oft-a composition formulated with apetroleum oil base stock of 5 centipoises to 70 poises, a thin uniformunbroken coating was produced on all surfaces.

All coatings referred to in this specification can be readily wiped offor dissolved completely in a brief dip in a suitable solvent cleanersuch as trichlorethylene.

It will be understood that thisspecification andexamples areillustrative only and are not limiting of the invention. a

2. A corrosioninhibiting composition soluble in both liquid hydrocarbonsand water consisting essentially of the amine salt reaction productconsisting essentially of from 9 to 25 parts by weight of caproic'acid,from 91 to 75 parts by Weight of'capryli-c acid, the total of caproicand caprylic acid being 100 par-ts, from 0.1 to 45 parts by weight ofalphamethylbenzylamine, and from to 135 parts by weight ofdicyclohexylarnine, the total of dicyclohexylamine andalpha-methylbenzylamine being from 80.1 to 150 parts by weight. v

3. A corrosion inhibiting composition soluble in both liquidhydrocarbons and water consisting essentially of the amine salt reactionproduct consisting essentially of from 15 to 25 parts by weight ofcaproic acid, from 75 to parts of caprylic acid, from 80 to parts byweight of dicyclohexylamine and from 45 to 30 parts by Weight ofalpha-methylbenzylamine.

4. A corrosion inhiibting composition suitable for application to Wetand damp metal surfaces, consisting essentially of from 85 to 99.9 partsby weight of an,

oleaginous vehicle of a viscosity of from 1 centipoise to 100 poises at25 C., and from 15 to 0.1 parts by weight of the amine salt reactionproduct consisting essentially of from 9 to 25 parts by weight ofcaproic acid, from v91 to 75 parts by Weight of caprylicacid,

of from 9 to 25 parts by weight of caproic acid, from 91 to 75 parts byweight of caprylic acid, the total of caproic and caprylic acids being100 parts, from 0.1 to 45 parts by weight of alpha-methylbenzylamine,and from 80 to parts by Weight of dicyclohexylamine, the total ofdicyclohexylamine and alpha-methylbenzylamine being from 80.1 to partsby weight.

6. A corrosion inhibiting composition suitable for application to wetand damp metal surfaces, consisting essentially of from 85 to 99.9 partsby weight of an oleaginous vehicle of a viscosity of from 1 centipoiseto 100 poises at 25 C., and from 15 to 0.1 parts by Weight of the aminesalt reaction product consisting essentially of from 15 to 25 parts byweight of caproic acid, from 75 to 85 parts of caprylic acid, from 80 to100 parts by Weight of dicyclohexylamine and from-45 to 30 parts byweight of alpha-methylbenzylamine.

7. A corrosion inhibiting composition suitable for application to Wetand damp metal surfaces, consisting essentially of (A) from 75 to 99.9parts by weight of an oleaginous vehicle of a viscosity of from 1centipoise to 100 poises at 25 C., (B) from 15 to 0.1 parts by Weight ofthe amine salt reaction product consisting essentially of from 9 to 25parts by weight of caproic acid, from 91 to 75 parts by weight ofcaprylic acid, the total of caproic and caprylic acids being 100 parts,and from 80 to 135 parts by weight of at least on cyclic amine selectedfrom the group consisting of cyclohexylamine and dicyclohexylamine, (C)and up to 10 parts by weight of a hydrophilic 7. suitable for use as ahydraulic fluid consisting essentially of (a) from 85 to 99.9 parts byweight of a fluid com prising a substantial proportion of an aqueousmedia and the balance being an oleaginous material and (b) from to 0.1%by weight of the amine salt reaction product consisting essentially offrom 9 to parts by Weight of caproic acid, from 91 to parts by weight ofcaprylic acid, the total of caproic and caprylic acids being parts, andfrom 80 to parts by weight of at least one cyclic amine selected fromthe group consisting of cyclohexylamine and dicyclohexylamine.

9. The aqueous fluid composition of claim 8 wherein the reaction productincludes from 0.1 to 45 parts by weight of alpha-methylbenzylamine.

References Cited by the Examiner UNITED STATES PATENTS Shields 252-64 XRSchaar 212.5

Senkus 21-2.5 Krieg 212.5 Drigot et a1. 10'6-14 Murray 106-14 XR 10JULIUS GREENWALD, Primary Examiner.

JOSEPH R. LIBERMAN, Examiner.

8. A CORROSION INHIBITED AQUEOUS FLUID COMPOSITION SUITABLE FOR USE AS AHYDRAULIC FLUID CONSISTING ESSENTIALLY OF (A) FROM 85 TO 99.9 PARTS BYWEIGHT OF A FLUID COMPRISING A SUBSTANTIAL PROPORTION OF AN AQUEOUSMEDIA AND THE BALANCE BEING AN OLEAGINOUS AMTERIAL AND (B) FROM 15% TO0.1% BY WEIGHT OF THE AMINE SALT REACTION PRODUCT CONSISTING ESSENTIALLYFROM 9 TO 25 PARTS BY WEIGHT OF CAPRIOC ACID, FROM 91 TO 75 PARTS BYWEIGHT OF CAPRYLIC ACID, THE TOTAL OF CAPRIOC AND CAPRYLIC ACIDS BEING100 PARTS, AND FROM 80 TO 135 PARTS BY WEIGHT OF AT LEAST ONE CYCLICAMINE SELECTED FROM THE GROUP CONSISTING OF CYCLOHEXYLAMINE ANDDICYCLOHEXYLAMINE.